Leather dyed with monoazo dyestuffs



Patented Jan. 30, 1940 UNITED STATES LEATHER DYED WITH MONOAZO DYESTUFFS Ernst Fellmer, Leverkusen-I. G.-Werk, Gustav Mauthe,

Cologne-Holweide, and Herman Noerr, Leverkusen-I. G.-Werk, signors to General Aniline Works, Inc.,

I New York, N. Y., a corporation of Delaware No Drawing. Application November I, 1936, igisal No. 109,678. In Germany November 9,

3 Claims.

The present invention relates to leather, particularly to chrome leather, dyed with certain azo dyestuffs.

When dyeing leather, particularly chrome leather, the grain or flesh side of which is more or less sharpened after dyeing, as for example kid leather, horse kid, nubuk (i. e., leather which has been fluffed on the grain side), velvet, hunting calf and so on, it is important not only to color the grain superficially, but also to dye the same shade for a certain depth, while the layer which remains undyed is intended to retain the clear greenish chromium color. Leathers which are dyed in this manner can be sharpened very well without spots becoming visible by the revealing of undyed parts.

In accordance with the present invention leather is dyed in the desirable manner above set forth. The present process is characterized by the use of dyestuffs of good solubility from diazo compounds of the aor p-naphthylamine series or their derivatives and meta-phenylenediamines, which may be substituted in the nucleus, or their derivatives which are substituted in one or both amino groups, for instance by alkyl, acyl, hydroxyalkyl, alkylsulfonic acid or alkylcorboxylic acid groups. It is suitable not to accumulate in the dyestufl molecule acid groups which do not exert a solubilizing action.

The following examples illustrate the invention:

Example 1 100 kgs. of shavers weight of a chrome tanned calf leather are brought into a drum with 200 ltrs. of water at a temperature of C. Into the rotating drum there is introduced through the hollow shaft 9. solution of 5 kgs. of the dyestufl which has been obtained by treating the monoazo dyestufi a-naphthylamine-3.6.8-trisulfonio acid-+2.4- toluylenediamine with 2 mols of glycol chlorhy- I drine under pressure at 120-130 C. After 45 minutes 3% of a fat liquor are added, and the drum rotated for a further 30 minutes. After the fat has been wholly taken up, 1% of technical formic acid of dissolved in ten times its quantity of water, is added in a thin jet and the drum rotated for a further hour. The leather is stroked out in the usual manner, dried, chipped,

I0 stretched, nailed and ilufled to nubuk.

The reddish brown dyeing can be sharpened very well. The dyestufl probably corresponds to the following formula:

NHC HIC H: 0 H

H038 N=N NHCH2CH2OH SOlH SOzH Emmple 2 kgs. of a chrome tanned neutralised calf leather are dyed in the usual manner from a bath containing 1.2 kgs. of the dyestufl obtained from diazotized l-naphthylamine-3.7-disulfonic acid plus 2.4-toluylenediamine-5-sulfonic acid (coupled in a weakly acid medium) of the following formula:

NH! $03K HO N CH:

' BOIH and 0.3 kg. of the dyestuif obtained by coupling of diazotized 4-nitro-1.3-phenylenediamine with the copper lake from diazotized 2-anisidine-4- suli'onic acid and resorcinol of the following foralone or in connection with other suitable acid or substantive dyestufls.

Further examples of the dyestufls which can be used in'accordance with the present invention as diazotizatlon components, and a compound of the group consisting of 1.3 diamino benzene, its

alkyl, nltro, halogen and -S01H substitution products and its N-hydroxy-alkyl, N-sulfo-alkyl,

5 and the shades obtained therewith are given N-carboxy-alkyl and N-acyl derivatives as couin the following table: 7 pling components.

Coupling component Dlazotization component Shade 10 acid (coupling'lnanalkaline medium); l-na hthylamine-ii-sulionic acid Light yellowish brown.

2 in an alkaline medium) Nap thionic acid Reddish light brown.

acid (coupling in an alkaline medium). -do Light brown. acid couplinginanalkailne medium) 1-naphthylamine-4.8-disulfonicacid Bluishli ht brown.

sulionic acid (coupling in an alkaline l-naphthylamine-Zl.6.8-trisulionic acid Reddish rown.

acetic acid (couplinginanacid medium) ..do Brown. I 2-naphthylamine-4.8-disulionic ac..d Brown.

in an acid medium) l-naphthy1amine-3.6-disulionic acid Brownish yellow. coupling in an alkaline medium). 2-naphthylamine4.8-dlsullonlc sc..d Light yellowish brown. inanscid medium S-naphthylamine-dS-disulionlc acid" Orange-brown. in an acid medium 2-naphthylamine4-sulionic acid Brownish yellow. (coupling in an dmel-naphthylamine-3.6.8-trisulionicacid Brown. coupling in an alkaline medium) 2-naphthylamine-6.8-disulionic acid Reddish brown. 20 in m dum 2-naghthylamine-5J-disulionic acid Yellowish brown.

analksline medium) o Orange-brown. an medium) 2-naphthylamine-4.8-disullonio acid.- Yellow-brown.

anacidmedium) 2-naphthylnmine-3.6-disulionicac Yeliowish brown. Do i-nitro-l-naphthylsmine t-sulionicaci Bluish brown-red. 2.4-toluylenedismine6-sulionlc acid (coupling in an acid medium) 4 aoletzilgid o l naphthylaminMi-sul- Yellowish brown.

, on c a 2.4-toiuylenediamine-5-sulionic acid (couplinginanalkaline medium). 2-naphthylamins-4.8-disulionic acid Yellowish brown.

Weclaim: 3. Leather dyed with an eas' ily soluble mono- 1. Leather dyed with an easily soluble monoazo -azo dyestufl derived from a naphthylamine suldyestufl. derived from a naphthylamine sulionic Ionic acid as diazotization component, and a comacid as diaozotization component, and 2.4-toluylpound of the group consisting of 1.3 diamino benenediamine-5-sulionic acid as coupling compozene, its alkyl, nitro, halogen and -SOaH subnent. stitution products and its N-hydroxy-alkyl, N- 2. Leather dyed with an easily soluble mono sulfo-alkyl. y a y de azo dyestufl derived from a compound of the lives 88 pl l mp en 35 group consisting of aand p-naphthylamines, the ERNST FELLMER.

nitroand acylamino substitution products thereof and the suli'onic acids of these compounds GUSTAV MAUTHE. HERMANN NOERR. 

